Aircraft weather radars display hazardous weather information based upon analyzed radar returns. Radar return information corresponding to detected hazardous weather information is presented to the aircraft crew on a display, typically using a plan view showing a geographic area over which the aircraft is traversing. Some radar systems may be optionally configured to present a selected portion of the hazardous weather information corresponding to a vertical slice view along a selected azimuth relative to the aircraft, such as along the aircraft's heading. Such a vertical slice displays the altitude and relative distance from the aircraft of any hazardous weather that lies along the selected vertical slice.
However, weather radars have a limited effective range. Radar range can be limited by terrain and the altitude of the aircraft. For example, an aircraft at cruising altitude over Kansas may have an effective radar range of about 300 nautical miles based upon the curvature of the earth and the output signal strength of the emitted radar signal. This effective range of the onboard radar may be referred to as the radar horizon. In Colorado, the effective range of the weather radar will be significantly reduced when mountain ranges block the emitted radar signals. When the aircraft is taking off or landing, the low altitude of the aircraft will result in a limited radar range since the earth horizon is relatively close to the aircraft (as compared to the earth horizon when the aircraft is at cruising altitude).
Accordingly, the weather radar will not show weather and/or objects of interest to the crew that is beyond the range of the weather radar. For example, the aircraft may be travelling at a relatively fast speed while at cruising altitude. Even though the effective range of the weather radar is several hundred miles out from the aircraft, the aircraft will traverse that distance in a relatively short period of time. Accordingly, it is desirable to effectively extend the range of an aircraft's weather radar so that the crew of the aircraft has more time to respond to adverse weather conditions and/or potentially dangerous objects, such as other aircraft.